Pentax SMC-DA 50-135mm f/2.8 ED (IF) SDM Interchangeable Lens Review

While Pentax got left behind a little at the dawn of the digital age, their recently announced lens roadmap shows they are coming back with a vengeance. This optic is the first in a series of professionally specified lenses to hit the marketplace.

Pentax SMC-DA 50-135mm Specification

• Lens Name: Pentax SMC-DA 50-135mm f/2.8 ED (IF) SDM
• Focal range: 50-135mm
• Optical Construction: 18-14 elements/groups
• Angle of view: 31.5 – 11.9°
• Max Aperture: f/2.8
• Min Aperture: f/22
• Closest focus: 1.0m
• Filter Thread: 67mm
• Dimensions: 76x136mm
• Weight: 0.32kg
• Price (SRP): £599.99
  

Pentax SMC-DA 50-135mm Build and handling
Offered as a Pro spec optic, the lens is well built and sealed, claiming dust and moisture proofing and, with Pentax’s long history of lens manufacture, it is not surprising that the lens feels very well built. It offers a new SDM focussing system (Sonic Drive Motor) that is the equivalent to USM and AF-S in its main competitors. It is just as quick and quiet as those predecessors.

he lens is a conventional, two ring design with both the zoom ring and the manual focus ring being large and well torqued. The SDM system allows manual over-ride of the focus ring without switching, and sports a ‘quick-shift’ switch for rapid change to full manual focus. A conventional distance window separates the two control rings.

he focussing is the biggest advance, with the f/2.8 aperture allowing plenty of light for the operation and the SDM motor achieving it with no fuss or hesitation.

Pentax SMC-DA 50-135mm Optical quality
The optical performance of this lens is up there with the best of them! Pentax have realised that they had to raise the bar optically now that everyone can look at the results at 100% and more, and in this offering they have exceeded expectations.

There is a hint of barrel distortion at the wide end of the zoom, which turns to a hint of pincushion at the longest focal length but that is about it! The short end does produce slightly better images than the longer end, but not by much and this is quite normal for any zoom lens. The edges of the frame keep up well with the centre of the glass. Good contrast throughout means that images are crisp and the colour rendition is spot on. Chromatic aberration exists, and can be measured but only just. To the naked eye it is invisible. Flare, unless deliberately induced, is exceptionally well controlled and no incidences of ghosting were seen.

top right: ME109 detail using 50mm top left: Catalina in flight shot at 135mm above left: 100% crop from previous shot right: RAF Falcon display team. Stack shot at 110mm

Pentax 50-135mm f/2.8 50mm at f/8	Pentax 50-135mm f/2.8 135mm at f/8
Pentax 50-135mm f/2.8 50mm at f/2.8	Pentax 50-135mm f/2.8 135mm at f/2.8

Pentax SMC50 135 chart1 Pentax SMC-DA 50-135mm Verdict
As one of the first in Pentax’s new lens line-up, this optic is impressive. OK, it’s not a cheap item, and with no need for in-lens stabilisation you might wonder at the price, but you do get what you pay for and this lens is both well built and specked and produces excellent results. I just hope the others in the proposed line-up are as good.

In summary, the positive points of the Pentax SMC-DA 50-135mm f/2.8 ED (IF) SDM are:

Good build and feel with dust and moisture sealing
Excellent optical performance
Fast and quiet autofocus

The negative points are:

Slight distortion at each end of the zoom range.
Expensive, although worth the money.

Check the latest price of the Pentax SMC-DA 50-135mm f/2.8 ED (IF) SDM here